Pipe cleaning apparatus

ABSTRACT

An apparatus and method for cleaning the inside of pipes by throwing abrasive material into contact with the internal surface of the pipe from a rotating wheel moving longitudinally therethrough, wherein the abrasive material and the material abraded from the pipe are expelled from an open end of the pipe during the cleaning operation by an air flow created by the rotating wheel. One embodiment of the invention includes a carriage movable into and out of the pipe, an abrading wheel rotatably mounted on a annulus tubular housing carried on the forward portion of the carriage, an auger conveyor for supplying the wheel with abrasive material, and a shroud mounted behind the wheel for reducing the effective cross-sectional area of the pipe. The rotating abrading wheel is inserted in one open end of the pipe and, as it is moved through the pipe, creates an air flow which moves the abrasive material and the material abraded from the pipe out of the opposite open end of the pipe. The abrasive material is then separated from the material abraded from the pipe for reuse on subsequent pipes. The abrading wheel is comprised of a front disc, a rear annular having an outer diameter less than the diameter of the disc and a plurality of blades interconnecting the disc and the annulus.

United States Patent [191 Hall, deceased et al.

[ PIPE CLEANING APPARATUS [76] Inventors: Wayne C. Hall, deceased, lateof Salt Lake City, Utah; by Scott D. Allen, executor, Oregon City,Oreg.; Wayne C. Hall, Jr., 20100 S. Beavercreek Rd., Oregon City, Oreg.97045 221' Filed: Nov. 1, 1972 21 Appl. No.: 302,637

Primary Examiner-Othell M. Simpson Assistant Examiner-Robert C. WatsonAttorney, Agent, or Firm-Roylance, Abrams, Berdo & Kaul 1 July 23, 197457] ABSTRACT An apparatus and method for cleaning the inside of pipes bythrowing abrasive material into contact with the internal surface of thepipe from a rotating wheel moving longitudinally therethrough, whereinthe abrasive material and the material abraded from the pipe areexpelled from an open end of the pipe during the cleaning operation byan air flow created by the rotating wheel. One embodiment of theinvention includes a carriage movable into and out of the pipe, anabrading wheel rotatably mounted on a tubular housing carried on theforward portion of the carriage, an auger conveyor for supplying thewheel with abrasive material, and a shroud mounted behind the wheel forreducing the effective cross-sectional area of the pipe. The rotatingabrading wheel is inserted in one open end of the pipe and, as it ismoved through the pipe, creates an air flow which moves the abrasivematerial and the material abraded from the pipe out of the opposite openend of the pipe. The abrasive material is then separated from thematerial abraded from the pipe for reuse on subsequent pipes. Theabrading Wh1i$2 r s1 of a rttse r nqrts 2 ing an outer diameter lessthan the diameter of the disc and a plurality of blades interconnectingthe disc and the annulus.

12 Claims, 7 Drawing Figures 1 PIPE CLEANING APPARATUS This inventionrelates to an apparatus and method for cleaning the internal surfaces oftubular goods, such as pipes, and more particulalry, it relatesto anapparatus and method for cleaning theinterior of pipes by means of anabrading wheel, wherein the abrading material used and the materialabraded from the pipe are both blown from the pipe during the cleaningoperation.

it is a common custom in the manufacture of metal pipes to produce pipesof various lengths and diameters and to stockpile them for futuredelivery. During the time the newly manufactured pipes remainstockpiled, the interior surfaces of the pipes may rust,'otherwise becorroded, or accumulate other foreign materials. Additionally, theinternal surfaces of the pipes usually contain a substantial degree ofmill scale. When specific pipes are ordered and immediate deliveryrequested, the interior surfaces of the pipes must be cleaned of themill scale and other accumulations to minimize the frictional resistanceto fluid flowing through the pipes and to enhance the adherence of aprotective coating which is applied to the interior surfaces of thepipes.

Various'attempts have been made in the past to pro vide apparatus forcleaning pipes described above;

however, they have been unsatisfactory because thay have beentime-consuming and expensive, and have generally necessitatedcomplicated equipment to ac-' complish the desired result.

One manner of cleaning the interior of pipes has been by sprayingabrasive materialfrom tubes directed at the interior surface of a pipe,which tubes are moved through the pipe as the pipe is rotated. Theabrasive material is forced through the tubes by compressed air.However, the cleaning results have not been totally satisfactory and,additionally, this process has been slow and has demanded large amountsof horsepower to pump the abrasive material and rotate .the pipe.

Attempts have also been made to utilize what is com- 7 monly referred toas a throwing or abrasive wheel which throws abrasive material into apipe lying horizontally to abrade the interior surface of the pipe. Thishas provided reasonable results in so far as cleaning is concerned;however, an additional step is necessitated to remove from the interiorof the pipe the abrasive material used in the cleaning operation and thematerial abraded from the pipe, which materials remain in the pipe afterthe cleaning operation. In order to overcome this problem, prior artdevices have been utilized which, after the interior of the pipe hasbeen cleaned, move the pipe into an upright position so the abrasivematerial and the abraded material flow from the pipe under the forces ofgravity. However, of course, this is a two-step process and necessitatesthe use of compli cated equipment having high horsepower requirements toinvert or otherwise elevate the usually rather heavy pipes which canweigh in excess of four tons. Other attempts have been directed towardsinitially positioning the pipe vertically and moving the abrading orthrowing wheel through the pipe to allow the abrasive material and theabraded material to fall by gravity out one end of the pipe. Likewise,this has necessitated the use of additional equipment and power to raiseand lower the pipe and is a two-step process.

It is therefore an object of the present invention to overcome thelimitations and drawbacks associated with the aforesaid prior artdevices and to provide a new and improved apparatus and method forcleaning pipes.

Another object of the present invention is to provide an apparatus forcleaning the interior of pipes without the necessity of elevating orotherwise inverting the pipe to be cleaned, and wherein the pipe mayremain in a horizontal plane during the cleaning operation.

A further object of the present invention is to provide a pipe cleaningapparatus and method which will expel the abrasive material and thematerial abraded from the internal surfaces of the pipe in one operationand reduce the time necessary to clean a pipe.

Another object of the present invention is to provide a pipe cleaningapparatus utilizing a throwing or abrading wheel which, in addition tocleaning the pipe, will also cause the abrasive material and thematerial abraded from the internal surfaces of the pipe to be expelledtherefrom by an air flow or pressure created by the abrading wheel.

Another object of the present invention is to provide an apparatus andmethod for cleaning the interior surfaces of a pipe by use of abrasivematerial wherein that material can be recycled and reused.

Other objects, advantages and salient features of the present inventionwill become apparent from the following detailed description, which,taken in conjunction with the annexed drawings, discloses a preferredembodiment of the present invention.

" In general, one embodiment of the apparatus includes a motor-drivencarriage for longitudinal movement into and out of an open ended pipelying horizontally, an abrading wheel rotatably mounted on a tubularhousing mounted on the carriage for feeding abrasive material againstthe sides of the pipe to clean them, an auger conveyor on the carriagecommunicating between a hopper carrying the abrasive material and theabrading wheel to supply the wheel with abrasive material, and a shroudmounted on the carriage between the hopper and the abrading wheel forreducing the effective cross-section of the pipe. An air pressure orflow generated by the rotating abrading wheel moves in an axialdirection along the pipe from one end to the other and expels theabrasive material and the material abraded from the pipe out one end ofthe pipe. The wheel is moved in a first direction into one open end of apipe and along the entire length of the pipe and then is moved in areverse direction and out of the pipe through the open end. The shroudhas a rubber seal along its periphery to provide for an adjustable fitbetween the shroud and pipes of various diameters. Additionally, anendless conveyor and supply hopper are provided for recycling theabrasive material used in the cleaning operation back to the hopper onthe carriage for reuse. A cabinet which receives the end of the pipeopposite from that initially receiving the carriage contains a vacuumpump for removing therefrom the lighter weight particles abraded fromthe internal surface of the pipe and an elevating conveyor for movingthe heavier shot or abrasive material which enters the cabinet to theendless conveyor for return to the supply hopper. The abrading wheel hasa front disc, a rear annulus and a plurality of blades interconnectingthe annulus and the disc.

Referring now to the drawings which form a part of this originaldisclosure:

FIG. 1 is a side elevational view of the overall system in accordancewith the present invention;

FIG. 2 is an elevational view in partial section showing the details ofthe carriage, the supply hopper, the auger conveyor, the shroud and theabrading wheel of one embodiment of the present invention;

FIG. 3 is a perspective view of the parts comprising the abrading wheeland part of the shaft which is connected to the wheel;

FIG. 4 is a sectional view of the shroud taken substantially along thelines 44 in FIG. 2;

FIGS is a sectional view of the auger conveyor and the supply hoppertaken substantially along lines 55 in FIG. 2;

FIG. 6 is a top plan view showing the details of the supply hopper andthe mechanism for actuating the supply hopper to feed abrasive materialtherefrom; and

FIG. 7 is an elevational view in partial section, similar to FIG. 2,showing a second embodiment of the present invention.

Referring now to the drawings in further detail, as seen in FIG. 2, theapparatus of the present invention in a first embodiment is generallydesignated 10 and comprises a carriage 12 and a material feedingassembly 14 comprising a supply hopper 48, an auger conveyor 16, ashroud l8 and an abrading wheel 20.

The carriage 12 is an elongated rectangular plate having at its frontend 13 two downwardly depending supports 24 having wheels 26 at theirends for engagement with the inner surface of a pipe 30. At the rear endof the carriage is a rectangular plate 27 suitably connectedperpendicular thereto for receiving one end of a support pipe 28 whichis in turn mounted on a motor-driven cart as will hereinafter bedescribed. An aperture 29 in the plate communicates with the interior ofthe pipe 28. Various lines used to supply electrical power andcompressed air to the apparatus are contained in the support pipe 28 andpass through the aperture 29 and to their respective motors valves andnozzles as will be described hereinafter. Mounted along the forward topportion of the carriage 12 on suitable supports 31 is an open endedtubular housing 32 having a forward end 34 and a rearward end 35. Theforward end has a reduced diamter 36.

As best seen in FIGS. 2, 5 and 6, evenly spaced along the top rearportion of the tubular housing 32 are a series of apertures 37 orientedin two-spaced rows extending longitudinally of the housing. The forwardend 34 of the tubular housing extends past the front end 13 of thecarriage l2 and has a cylindrical shroud 18 concentrically mountedthereto. As seen in FIGS. 2 and 4, the shroud, which is a rightcylindrical open-ended pipe, has a radius equal to approximately threetimes the radius of the tubular housing and is supported on the housingby four equally spaced spokes 38 attached to the surface of the housingand the inner surface of the shroud. Suitably connected to the exteriorsurface of the shroud 18 is a thin collar 40 having a rubber extensionring 42 surrounding the periphery of the collar to span the spacebetween the collar and the pipe 30. The front end of the shroud isadjacent the forward end of the housing 32.

As best seen in FIGS. 2, 5 and 6, a variable feed supply hopper 48 ismounted longitudinally on the top of the tubular housing 32 extendingfrom adjacent the rear end of the shroud 18 to substantially the otherend of the tubular housing. As seen in FIGS. 5 and 6, the hopper 48 isformed on its sides by two elongated rectangular side plates 50 and 51mounted along their bottom edges at an angle less than 90 to the outersurface of the tubular housing along lines parallel to the longitudinalaxis of the housing and at its ends by end plates 74 and 76 which havebottom edges conforming to and resting on the circular top of thehousing 32. An inverted V-shaped member 52, formed from two elongatedplates jointed at an angle, is interposed between the plates 50, 51, 74and 76 to form two troughs in the hopper 48 so that the hopper has aW-shaped crosssection. As seen in FIG. 5, the side edges 73 of themember 52 rest along the lines formed by the intersection of the tubularhousing 32 and the plates 50 and 51. Spaced along the edges 73 are aseries of rectangular cut-outs 71 which spacing coincides with thelongitudinal spacing of the apertures 37 formed in the top of thetubular housing. The length of the member 52 is less than that of thehopper 48 and therefore can be reciprocated longitudinally thereof to aposition where the cut-outs 71 coincide with the apertures 37 whereinabrasive material in the hopper is allowed to flow through the aperturesor to a position where the cutouts 71 do not coincide with the apertures37 wherein abrasive material in the hopper is prevented from flowingthrough the apertures. The front end of the member 52 has a rod 75mounted in the apex of that member which is slidable along aninvertedV-shaped guide 77 mounted to the end plate 74. Similarly, rod 79is mounted at the other end of the member 52 in the apex of that memberfor slidable movement through a pipe 81 fitted into a suitably providedbore in the end wall 76. As seen in FIG. 6, one end of the rod 79 ispivotally connected to the middle of a rod 83 which is pivotally mountedat one end to a support 85 extending from the end plate 76 and pivotallymounted to a piston shaft 60 at its other end. The shaft 60 is connectedto a piston 62 enclosed by and movable through an air cylinder 64. Aconventional four-way solenoid valve 66 has conduits 63 and 65 connectedto respective sides of the piston 62 in the air cylinder 64, whereby theinterconnected member 52 may be moved longitudinally along the tubularhousing 32 on actuation of the valve 66 to allow abrasive material inthe hopper 48 to flow into the tubular housing. That valve has aconnection by line 67 to a suitable air pressure line carried in thesupport pipe 28 and an outlet line '69 to the atmosphere.

As seen in FIG. 2, mounted for rotation within the tubular housing 32 onbearings 45 and 47, which are supported at respective ends 34 and 35 ofthe housing, is

a shaft 90. The shaft is connected at its rear end to a motor 92 bymeans of belts 93, which motor is located adjacent the rear of thehousing 32 and on the carriage 12, and at its front end to the abradingwheel 20. A power line for the motor 92 is carried in the support pipe28, and on actuation the motor causes the shaft and the abrading wheel20 to rotate.

Mounted for rotation on the shaft 90 and within the tubular housing 32is the auger conveyor 16 which is comprised of a pipe 44 having a lengthsubstantially equal to the length of the tubular housing and a radiusequal to substantially one-half the radius of the tubular. housing.Mounted on that pipe is a helical member 46 which extends the entirelength of the pipe. Bearings 55 and 57, located on the inside of theends of the pipe 44, support the pipe 44 on the shaft 90 and allow theauger to rotate relative to the shaft 90.

As seen in FIG. 2, a motor 78 is mounted to the rear portion of thecarriage 12 adjacent the support plate 27 and has a motor shaft 80connected thereto with a sprocket 87 at its end. A chain belt 89connects the sprocket 87 on the shaft 80 to a sprocket 91 on the rear ofa shaft 180 rotatably mounted along the top of the carriage 12. On thefront of the shaft 180 is a sprocket 82 which is connected via a chainbelt 84 passing through a cut-out 86 in the bottom of the tubularhousing 32 to a sprocket 88 connected to the rear end of the pipe 44carrying the helical member 46. Actuation of the motor'78 causes theauger conveyor to rotate and feed abrasive material in the tubularhousing towards the wheel 20.

As seen in FIGS. 2 and 3, the abrading wheel 20 is comprised of a front,circular plate or disc 94, a rear, circular plate or annulus 96 and aseries of eight equally radially spaced rectangular throwing blades 98.The diameter of the front disc 94 is approximately threequarters theinside diameter of the shroud, the inner diameter of the rear annulus96- is substantially equal to the inner diameter of the tubular housing32 and the outer diameter of the rear annulus 96 is slightly smallerthan the diameter of the front disc 94. Concentrically mounted to oneside of the front disc 94 by bolts 95 is a smaller disc 100 which isintegrally formed with one end of a tubular hub 102 which passes througha suitably drilled central bore 93 in the front disc 94 and extendsrearwardly substantially to the front end 34 of the tubular housing. Thefront of the shaft 90 passes through a cylindrical bore 104 in the hub102 and extends into a central bore in the smaller disc 100. A smallradius disc 105 is bolted to the end of the shaft 90 to keep the wheel20 from moving off the shaft. A key 106 passes through a slot in thesurface of the shaft 90 and a slot 101 in the hub 102 to connect-thesetwo members and prevent relative rotation between them. The front disc94 and the rear annulus 96 are oriented parallel and concentric to eachother. The eight blades 98 are equally radially spaced around the hub102 such that their outer ends are coincident with the exteriorperiphery of the front disc 94 and their inner ends are just slightlyspaced from the exterior periphery of the hub 102. Each blade 98 issuitably attached along opposite sides to the front disc and the rearannulus and is in a plane perpendicular to the planes of the annulus anddisc. If desired, slots in the disc and annulus may be provided toreceive the edges of the blades. An annular inlet 95 in the wheel 20 isformed between the end of the hub 102 and the inner radius of theannulus 96 which is partially received around the reduced diameter 36 ofthe housing 32. I

Also included in the material feeding assembly 14 and located on thebottom side of the shroud 18 in front of the collar 40 is an arcuate,closed ended pipe 108 which communicates with an air line 110 suitablymounted to the carriage 12 and passing through a suitably formed bore112 in the bottom of the shroud 18. As seen in FIG. 4, a plurality ofarcuately spaced orifrees 114 are provided in the portion of the arcuatepipe facing forward. The free end of the air line 110 is connected to asource of compressed air capable of providing approximately 90 poundsper square inch of pressure. Line 110 is provided with air through aline carried in the support pipe 28.

As mentioned above with regard to the description of the abrading wheel20, the rear annulus 96 has an outer diameter which is slightly lessthan the diameter of the front disc 94. It has been discovered that whenthe rear annulus has such a reduced diameter and a shroud, having adiameter equal to substantially 4/3 of the diameter of the front disc,is positioned adjacent the rear annulus and when the wheel and theshroud are moved through a pipe having a diameter substantially largerthan the shroud, an air pressure or flow is created by the rotation ofthe abrading wheel, which flow moves along the longitudinal axis of thepipe from one open end to the other open end in a direction from therear annulus towards the front disc. If the front and rear plates on theabrading wheel are of equal diameter no air flow directed down the pipeis created. Thus, in the operation which will be described hereinafterthe rotating wheel both throws abrasive material to clean the walls ofthe pipe and additionally creates an air pressure or flow along thelength of the pipe to blow the abrasive material and the abradedmaterial out the rear end of the pipe. As shown in FIG. 2, thecombination of the shroud 18, the collar 40 and the rubber extension 42effectively reduces the diameter of the pipe 30 which is larger thanthat of the shroud to the proper 4:3 ratio. This is indicated in FIG. 2wherein the diameter of the shroud is designated A and the diameter ofthe front disc is designated A.

As seen in FIG. 7, a second embodiment in accordance with the presentinvention is presented. It has also been discovered that when thediameter of the pipe being cleaned is substantially in a ratio of 4:3with the diameter of the front disc of the abrading wheel being used theshroud is not necessary to aid in creating the desired air blast. Thisrelationship is indicated in FIG. 2 wherein the diameter of the pipe isdesignated A and the diameter of the front disc is designated A. FIG. 7contains all of the apparatus as that shown in FIG. 2 except the shroud,the spokes, the collar and the rubber extension ring, which are notutilized. Those same parts are given the same character numerals.

The overall operation of both embodiments is essentially the same;however, the two different embodiments are utilized, with the abovementioned differences in structure, when the relationship of thediameter of the pipe and the front disc is as set forth above. With onlythe addition of the shroud, an abrading wheel of one size may be used toclean pipes of various diameters.

As seen in FIG. 1, the apparatus 10 can be incorporated in an overallsystem for delivering a pipe to be cleaned to a position adjacent thefront end of the apparatus with the pipe lying horizontally. Variousconveyors and hoppers also are utilized to return used abrasive materialback to the hopper for reuse.

Specifically, in FIG. 1, the apparatus 10 is shown with the support pipe28 mounted to a cart 116 which is motor-driven and guided on rails 117.The drive for the cart is preferably of variable speed and reversible.The support pipe rides along a hydraulicallyelevated roller 118 as thecart moves the entire apparatus 10 into the front end 39 of the pipe 30and then along its entire length. The cart is then actuated to move theapparatus in the reverse direction and out of the front end 39 of thepipe 30. That pipe and others like it are rolled into position adjacentto. the front of the apparatus along suitable supports 120 and held inplace by wedges 121. Preferably, the pipes are oriented in a planehorizontal to the ground. The front end 39 of the pipe can be receivedina shroud (not shown) so that if abrasive material is sprayed from theapparatus beforethe wheel enters the pipe, that material will beconfined in the shroud. A rear end 33 of the pipe 30 is positionedwithin a suitable opening in a housing or cabinet 122 which has asloping bottom 124 and an elevating bucket conveyor 126 at the rear ofit and extending from the lowest portion of the sloping bottom 124 to aposition above the cabinet. Located to receive material discharged'romthe buckets in the elevating conveyor 126 is an endless belt conveyor128 having a delivering end 129 located above a reservoir hopper 130which is suitably supported on supports 132 in a position to supply thehopper 48 on the carriage 12 when the apparatus is removed from the pipe30. Additionally, the cabinet 122 has a vacuum pump 134 communicatingwith the interior thereof to remove lightweight particles suspended inthe volume enclosed by the cabinet and to transfer them to a dustcollector 123. These particles comprise the material cleaned from thepipe.

In the preferred embodiment of the present invention actually built andoperated the electrical motor 92, used to run the abrading wheel, is 20hp and capable of rotating the wheel by suitable gearing arrangements atapproximately 2,600 rpm. The electrical motor 78, used to run the augerconveyor, is a hp motor and capable of rotating the auger conveyor bysuitable gearing arrangements at approximately 200 rpm. Preferably, thepipe 44 incorporated in the auger conveyor has an inner diameter of4'inches, the tubular housing 32 has an inner diameter of 8 inches andthe helical member 46 has an outer diameter of 7 inches. The shaft 90rotated by the motor 92 and supporting the abrading wheel 20 has a2-inch diameter with the forward disc 94 having a diameter ofapproximately 19.5 inches and the rear annulus having an outer diameterof l 7 inches withan interior diameter of 8.5 inches. The longitudinallength of the supply hopper 48 is 7 feet, the longitudinal length of theshroud 18 is l foot and the diameter of the shroud is 26 inches. Thepipes to be cleaned by an apparatus having the above-mentioneddimensions can beas small as 30 inches and can be of a length ofapproximately 40 feet. Pipes of larger diameters and lengths can beoperatedon with a concomitant adjustment of the dimensions of theapparatus as necessary. Additionally, the rubber ring 42 surrounding thecollar 40 can be provided in various thicknesses to accommodate largerdiameter pipes. Utilization of the apparatus described herein hasreduced the time necessary to clean one pipe from minutes using oldmethods to 5 minutes. And additionally horsepower requirements have beenreduced from approximately 600 to approximately 50.

In operation, the pipe to be cleaned, as seen in FIG. 1, is manipulatedon the supports 120 so that a front end 39 is adjacent the front of theabrading wheel, and the rear end 33 is partially received in the cabinet122, and the pipe 30 is lying in a horizontal plane. The abrasivematerial, which can be steel or iron grit or other suitableshot-blasting" material, is contained in the reservoir hopper 130located above the apparatus 10,

and is delivered to the variable feed supply hopper 48 I mounted on thecarriage 12 to fill it substantially to the top of the side walls 50 and51.

The motorized cart 116 is actuated to move the apparatus in a firstdirection into the front open end 39 of the pipe and completely alongthe length of the pipe 30 as seenin FIG. 2 with the height of theapparatus relative to that end 37 being adjusted by the hydraulicallyelevated roller 118. As the apparatus moves through the pipe, theforward end of the apparatus 10 is supported on the bottom of the insideof the pipe on the wheels 26 connected to the carriage 12. Preferably,the speed at which the cart 116 moves the apparatus 10 through the pipeis approximately l3.5 feet per minute in a 40 foot pipe. However, sincethe motorized cart 1 16 can be moved at varying speeds, any desiredspeed may be utilized. Just before the front of the abrading wheel 20enters the pipe, the motors 92 and 78 are actuated to begin rotation ofthe abrading wheel and the auger conveyor 16, which conveyor will feedthe abrasive material which will be fed to it from the supply hopperthrough the apertures 37 and to the abrading wheel through the inlet 95formed between the hub 102 and the rear annulus 96.

At this time, the solenoid valve 66 is also operated to in turn movethemember 52 to uncover the apertures 37 in the tubular housing to allowthe abrasive material in the hopper 48 to pass into the tubular housing32 through those apertures 37. The amount of abrasive material fed intothe tubular housing can be as much as desired taking into considerationthe speed at which the apparatus is to move through the pipe and thespeed at which the abrading wheel is rotating. However, it is desiredthat at no time the abrasive material in the tubular housing be allowedto completely fill that housing so that a clear passageway is providedin the housing from the open rear end 365 to the open forward end 34.This allows air to move through the tubular housing and through theannular inlet 95 as will be described hereinafter.

The combination of the rapidly rotating blades 98 on the abrading wheeland the forces exerted on the abrasive material by therotating augerconveyor feed the abrasive material along the tubular housing into thecenter of the abrading wheel through inlet 95. From that center pointthe abrasive material is thrown substantially perpendicularly to thelongitudinal axis of the pipe to be cleaned and impinges upon theinternal surface of the pipe with great force. This impinging actionremoves various mill scale and corrosion and other foreign materialwhich have accumulated on the internal surface of the pipe. Also,because of the unique configuration of the wheel as described above, anair flow is created within the pipe along which air moves into the frontopen end 39 of the pipe, along the pipe behind the apparatus 10, throughthe tubular housing 32, through the shroud 18, through and around theabrading wheel, along the pipe ahead of the apparatus 10, and finallyout the rear open end 33 of the pipe.

This stream of air carries the abrading material thrown from theabrading wheel and also the material removed from the pipe by theabrading action of the abrading material towards the end of the pipelocated in the cabinet 122. Due to this air flow in combination with themovement of the entire apparatus in a first direction from the frontopen end 39 of the pipe towards the rear open end 33, the material ismoved into the cabinet 122. Most of the material is carried by the airflow completely along the length of the pipe and into the cabinet 122.However, some of the material might only move along a portion of thepipe and not directly into the cabinet, this material is transferredinto the r 9 cabinet as the apparatus moves through the entire pipe.

Additionally, the air line 110, which is connected to a high pressureair compressor, can be actuated to deliver compressed air through theorifices 114 in the arcuate pipe 108 suspended below the shroud 18. Ifany of the material accumulates at the bottom of the pipe, it is movedalong by the additional thrust added to the air stream by the highpressure air emanating from the pipe 108.

At the end of the pipe, the abrasive material and the material removedfrom the internal surface of the pipe enter the cabinet 122. The heavierabrasive material rolls along the sloping bottom wall 124 and is thenelevated by the buckets in the conveyor 126 and deposited on the endlessbelt conveyor 128. From that conveyor 128 the abrasive material isreturned to the reservoir hopper 130 for reuse on subsequent pipes. Thematerial removed from the internal surface of the pipe, being lighterthan the abrasive material, is suspended in the volume enclosed by thecabinet and is removed therefrom by the vacuum pump 134 and collected ina dust container 123.

After the apparatus has been moved completely through one pipe and hascleaned its entire length, the motorized cart 116 is stopped, and themotors 92 and 78 are turned off, as is the infeed of compressed air tothe air line 110 and the feed of abrasive material from the supplyhopper 48. Then the motorized cart 116 is energized in a reversedirection to move the apparatus in a direction opposite from the firstdirection along the length of the pipe and finally out of the front end39 of the pipe 30. The hopper 48 is then refilled from the reservoirhopper 1'30 and a new pipe is maneuvered into position along thesupports 120 replacing the cleaned pipe and the operation outlined aboveis repeated for subsequent pipes.

The operation of the second embodiment shown in FIG. 7 is the same asthe first embodiment except that the pipe itself takes the place of theshroud.

While two advantageous embodiments have been chosen to illustrate theinvention, it will be understood by those skilled in the art thatvarious changes and modifications can be made therein without departingfrom the scope of the invention as defined in the appended claims.

What is claimed is:

1. An apparatus for cleaning the interior walls of a pipe, thecombination comprising:

a carriage;

means for moving said carriage through a pipe in a first direction;

material feeding means coupled with said carriage for dischargingabrasive material against the interior walls of said pipe; and

said material feeding means also providing an air flow through said pipein said first direction;

whereby said abrasive material is discharged into contact with theinterior walls of said pipe to clean them and is then carried with thematerial cleaned from the walls in said first direction by said airflow,

wherein said material feeding means includes a plurality of blades forthrowing said abrasive material.

2. An apparatus for cleaning the interior walls of a pipe, thecombination comprising:

a carriage;

means for moving said carriage through a pipe in a first direction;

material feeding means coupled with said carriage for dischargingabrasive material against the interior walls of said pipe; and

said material feeding means also providing an air flow through said pipein said first direction;

whereby said abrasive material is discharged into contact with theinterior walls of said pipe to clean them and is then carried with thematerial cleaned from the walls in said first direction by said airflow,

wherein said material feeding means includes a circular front plate;

a circular rear plate having an outer diameter less than the diameter ofsaid front plate;

a plurality of blades interconnecting said front and rear plates; andmeans connected to said front plate for rotating said front plate.

'3. An apparatus for cleaning the interior walls of a pipe, thecombination comprising:

a carriage;

means for moving said carriage through a pipe in a first direction;

material feeding means coupled with said carriage for dischargingabrasive material against the interior walls of said pipe; and

said material feeding means also providing an air flow through said pipein said first direction;

whereby said abrasive material is discharged into contact with theinterior walls of said pipe to clean them and is then carried with thematerial cleaned from the walls in said first direction by said airflow,

wherein said material feeding means includes rotating blade means forthrowing said abrasive material in a direction substantiallyperpendicular to said first direction into contact with the interiorwalls of said pipe and for generating said air flow; and

means coupled to said rotating blade means for directing said air flowin said first direction.

4. An apparatus according to claim 3 wherein said material feeding meansincludes:

conveyor means for feeding said abrasive material in said firstdirection to said rotating blade means.

,5. An apparatus according to claim 4 wherein said material feedingmeans includes:

a hopper means for feeding abrasive material to said conveyor means.

6. An apparatus according to claim 5 wherein said material feeding meansincludes:

a shroud means mounted adjacent said rotating blade means for reducingthe cross-sectional area of the pipe.

7. An apparatus according to claim 6 and further including:

means located at one end of the pipe for separating said abrasivematerial and said material cleaned from the walls; and

means, coupled to said means for separating, for transferring saidabrasive material back to said hopper means.

8. An apparatus according to claim 7 and further including:

support means for positioning said pipe in a substantially horizontalplane; and

to the longitudinal axis of the pipe.

11. An apparatus according to claim 3 wherein said material feedingmeans includes a shroud means mounted adjacent said rotating blade meansfor reducing the cross-sectional area of the pipe.

12. An apparatus according to claim 3 wherein said means for directingsaid air flow includes front and rear plates.

1. An apparatus for cleaning the interior walls of a pipe, thecombination comprising: a carriage; means for moving said carriagethrough a pipe in a first direction; material feeding means coupled withsaid carriage for discharging abrasive material against the interiorwalls of said pipe; and said material feeding means also providing anair flow through said pipe in said first direction; whereby saidabrasive material is discharged into contact with the interior walls ofsaid pipe to clean them and is then carried with the material cleanedfrom the walls in said first direction by said air flow, wherein saidmaterial feeding means includes a plurality of blades for throwing saidabrasive material.
 2. An apparatus for cleaning the interior walls of apipe, the combination comprising: a carriage; means for moving saidcarriage through a pipe in a first direction; material feeding meanscoupled with said carriage for discharging abrasive material against theinterior walls of said pipe; and said material feeding means alsoproviding an air flow through said pipe in said first direction; wherebysaid abrasive material is discharged into contact with the interiorwalls of said pipe to clean them and is then carried with the materialcleaned from the walls in said first direction by said air flow, whereinsaid material feeding means includes a circular front plate; a circularrear plate having an outer diameter less than the diameter of said frontplate; a plurality of blades interconnecting said front and rear plates;and means connected to said front plate for rotating said front plate.3. An apparatus for cleaning the interior walls of a pipe, thecombination comprising: a carriage; means for moving said carriagethrough a pipe in a first direction; material feeding means coupled withsaid carriage for discharging abrasive material against the interiorwalls of said pipe; and said material feeding means also providing anair flow through said pipe in said first direction; whereby saidabrasive material is discharged into contact with the interior walls ofsaid pipe to clean them and is then carried with the material cleanedfrom the walls in said first direction by said air flow, wherein saidmaterial feeding means includes rotating blade means for throwing saidabrasive material in a direction substantially perpendicular to saidfirst direction into contact with the interior walls of said pipe andfor generating said air flow; and means coupled to said rotating blademeans for directing said air flow in said first direction.
 4. Anapparatus according to claim 3 wherein said material feeding meansincludes: conveyor means for feeding said abrasive material in saidfirst direction to said rotating blade means.
 5. An apparatus accordingto claim 4 wherein said material feeding means includes: a hopper meansfor feeding abrasive material to said conveyor means.
 6. An apparatusaccording to claim 5 wherein said material feeding means includes: ashroud means mounted adjacent said rotating blade means for reducing thecross-sectional area of the pipe.
 7. An apparatus according to claim 6and further including: means located at one end of the pipe forseparating said abrasive material and said material cleaned from thewalls; and means, coupled to said means for seParating, for transferringsaid abrasive material back to said hopper means.
 8. An apparatusaccording to claim 7 and further including: support means forpositioning said pipe in a substantially horizontal plane; and whereinsaid first direction is along the longitudinal axis of said pipe.
 9. Anapparatus according to claim 8 wherein said material feeding meansincludes: means coupled to said carriage for supplying air underpressure along the bottom of said pipe.
 10. An apparatus according toclaim 1 wherein said plurality of blades are coupled to a shaftrotatably coupled to said carriage, said shaft being oriented parallelto the longitudinal axis of the pipe.
 11. An apparatus according toclaim 3 wherein said material feeding means includes a shroud meansmounted adjacent said rotating blade means for reducing thecross-sectional area of the pipe.
 12. An apparatus according to claim 3wherein said means for directing said air flow includes front and rearplates.